Message-ID: <63445f2f-a0bb-153c-0e15-74a09ea26dc1@sberdevices.ru>
Date:   Sun, 19 Mar 2023 21:51:06 +0300
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In-Reply-To: <e141e6f1-00ae-232c-b840-b146bdb10e99@sberdevices.ru>
To:     Stefan Hajnoczi <stefanha@redhat.com>,
        Stefano Garzarella <sgarzare@redhat.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Bobby Eshleman <bobby.eshleman@bytedance.com>
CC:     <kvm@vger.kernel.org>, <virtualization@lists.linux-foundation.org>,
        <netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <kernel@sberdevices.ru>, <oxffffaa@gmail.com>,
        <avkrasnov@sberdevices.ru>
From:   Arseniy Krasnov <avkrasnov@sberdevices.ru>
Subject: [RFC PATCH v1 1/3] virtio/vsock: fix header length on skb merging
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This fixes header length calculation of skbuff during data appending to
it. When such skbuff is processed in dequeue callbacks, e.g. 'skb_pull()'
is called on it, 'skb->len' is dynamic value, so it is impossible to use
it in header, because value from header must be permanent for valid
credit calculation ('rx_bytes'/'fwd_cnt').

Fixes: 077706165717 ("virtio/vsock: don't use skbuff state to account credit")
Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
---
 net/vmw_vsock/virtio_transport_common.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index 6d15cd4d090a..3c75986e16c2 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -1091,7 +1091,7 @@ virtio_transport_recv_enqueue(struct vsock_sock *vsk,
 			memcpy(skb_put(last_skb, skb->len), skb->data, skb->len);
 			free_pkt = true;
 			last_hdr->flags |= hdr->flags;
-			last_hdr->len = cpu_to_le32(last_skb->len);
+			le32_add_cpu(&last_hdr->len, len);
 			goto out;
 		}
 	}
-- 
2.25.1